Yes, they do hide reviews regularly - and their marketing team basically tells you if you own a business listed on Yelp with correct information. Positive reviews get hidden for non-advertisers, negative ones for advertisers. In essence when you switch from consumer side to business-owner side, the site goes from a friendly place to post reviews into a vicious protection racket - i.e. "That's a nice reputation you got there, pal. Be a shame if something... happened to it, y'know?" I wish that was so very different than what their official team members said on the phone.